The updated heatwave plan warns that ozone levels rise in hot weather, but fall in the evenings. It recommends that those with respiratory problems should stay indoors during the hottest part of the day with windows shaded and closed when the temperature is warmer outside than in.

The DoH advises anyone who has concerns for themselves or a vulnerable friend to contact their local environmental health officer. It also recommends that carers identify those most at risk before the hot weather begins.

The plan sets out four levels of heat alert, ranging from ‘normal’ (level one) to level four, triggered when a heatwave is so severe or prolonged that its effects extend outside health and social care, such as power or water shortages.